Generator Ratings

 Includes a heavy-duty 25-foot adapter cord set with a generator-compatible plug at one end and four female outlets at the other.  Runs 4.4 hours when connected to a standard portable 20-pound liquid-propane tank.  Discontinued but might still be available.  Includes an automatic transfer switch.  When connected to a 250-gallon residential liquid propane tank; runtime essentially infinite with a natural-gas hookup.  Includes a manual transfer switch.

Guide to the Ratings

Overall score is based on emergency power, power quality, ease of use, run time, and noise. Emergency power is the capacity to deliver enough wattage to run essential devices such as a well pump, refrigerator, lights, and a heater or window a/c at once. Power quality is the ability to deliver consistent voltage. Ease of use includes starting, fuel shutoff, panel features, and (for portables) transport. Tested run time is how long the unit provided 80 percent capacity on a full tank of gasoline (portables) or a 250-gallon tank of liquid propane (stationary). Noise is at 50 feet with generator 3 feet from a building. Claimed output is the manufacturer’s rated maximum electrical output. Tested output is our measure of maximum sustained wattage. Price is approximate retail.